---
id: 587d78b0367417b2b2512b05
title: Criar uma página de documentação técnica
challengeType: 14
forumTopicId: 301146
dashedName: build-a-technical-documentation-page
---

# --description--

**Objetivo:** Construa um aplicativo que com uma função semelhante a <a href="https://technical-documentation-page.freecodecamp.rocks" target="_blank" rel="noopener noreferrer nofollow">https://technical-documentation-page.freecodecamp.rocks</a>. **Não copie a demo desse projeto**.

**Histórias de usuário:**

1. Deve haver um elemento `main` com um `id="main-doc"` correspondente, que contenha o conteúdo principal da página (documentação técnica)
1. Dentro do elemento `#main-doc`, deve haver vários elementos `section`, cada um com a classe `main-section`. Deve haver, pelo menos, cinco
1. O primeiro elemento de cada `.main-section` deve ser um elemento `header` que contenha o texto que descreve o tópico daquela seção.
1. Cada elemento `section` com a classe `main-section` também deve ter um `id` que corresponda ao texto de cada `header` contido dentro dela. Os espaços existentes devem ser substituídos por sublinhados (por exemplo, a seção que contém o cabeçalho "JavaScript and Java" deve ter um `id="JavaScript_and_Java"`)
1. Os elementos `.main-section` devem conter, juntos, pelo menos dez elementos `p` no total (não 10 para cada elemento)
1. Os elementos `.main-section` devem conter, juntos, pelo menos cinco elementos `code` no total (não 5 para cada elemento)
1. Os elementos `.main-section` devem conter, juntos, pelo menos cinco elementos `li` no total (não 5 para cada elemento)
1. Deve haver um elemento `nav` com um `id="navbar"` correspondente
1. O elemento da barra de navegação (navbar) deve conter um elemento `header` que contenha o texto que descreve o tópico da documentação técnica
1. Além disso, a barra de navegação deve conter elementos de âncora (`a`) com a classe `nav-link`. Deve haver um para cada elemento com a classe `main-section`
1. O elemento `header` em `#navbar` deve vir antes de qualquer elemento de link (`a`) na barra de navegação
1. Cada elemento com a classe `nav-link` deve conter um texto que corresponda ao texto do `header` dentro de cada `section` (exemplo: se você tem uma seção/cabeçalho "Olá mundo", sua barra de navegação deve ter um elemento que contenha o texto "Olá mundo")
1. Ao clicar em um elemento da barra de navegação, a página deve navegar para a seção correspondente do elemento `#main-doc` (exemplo: ao clicar em um elemento `.nav-link` que contenha o texto "Olá mundo", a página deve navegar para o elemento `section` que tenha esse id e contenha o cabeçalho correspondente)
1. Em dispositivos com tamanho regular (laptops, desktops), o elemento com `id="navbar"` deve ser mostrado no lado esquerdo da tela e deve sempre estar visível para o usuário
1. A documentação técnica deve utilizar pelo menos uma media query

Atenda às histórias de usuário e passe em todos os testes abaixo para concluir este projeto. Dê ao projeto o seu próprio estilo pessoal. Boa programação!

**Observação:** não se esqueça de adicionar `<link rel="stylesheet" href="styles.css">` em seu HTML para vincular sua folha de estilo e aplicar seu CSS

# --hints--

Você deve ter um elemento `main` com o `id` `main-doc`.

```js
const el = document.getElementById('main-doc')
assert(!!el)
```

Você deve ter pelo menos cinco elementos `section` com a classe `main-section`.

```js
const els = document.querySelectorAll('#main-doc section')
assert(els.length >= 5)
```

Todos os elementos com a classe `.main-section` devem ser elementos `section`.

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if (el.tagName !== 'SECTION') assert(false)
})
assert(els.length > 0)
```

Você deve ter pelo menos cinco elementos `.main-section` aninhados dentro de `#main-doc`.

```js
const els = document.querySelectorAll('#main-doc .main-section')
assert(els.length >= 5)
```

O primeiro filho de `.main-section` deve ser um elemento `header`.

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if(el.firstElementChild?.tagName !== 'HEADER') assert(false)
})
assert(els.length > 0)
```

Nenhum dos elementos `header` deve estar vazio.

```js
const els = document.querySelectorAll('header')
els.forEach(el => {
  if (el.innerText?.length <= 0) assert(false)
})
assert(els.length > 0)
```

Todos os elementos com a classe `.main-section` devem ter um `id`.

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  if (!el.id || el.id === '') assert(false)
})
assert(els.length > 0)
```

Cada `.main-section` deve ter um `id` que corresponda ao texto de seu primeiro filho, e todos os espaços no texto do filho devem ser substituídos por sublinhados (`_`) no id.

```js
const els = document.querySelectorAll('.main-section')
els.forEach(el => {
  const text = el.firstElementChild?.innerText?.replaceAll(' ', '_')
  if (el.id?.toUpperCase() !== text?.toUpperCase()) assert(false)
})
assert(els.length > 0)
```

Você precisa ter, pelo menos, 10 elementos `p` (ao todo) dentro dos elementos `.main-section`.

```js
const els = document.querySelectorAll('.main-section p')
assert(els.length >= 10)
```

Você precisa ter, pelo menos, cinco elementos `code` (ao todo) dentro dos elementos `.main-section`.

```js
const els = document.querySelectorAll('.main-section code')
assert(els.length >= 5)
```

Você precisa ter, pelo menos, cinco elementos `li` dentro dos elementos `.main-section`.

```js
const els = document.querySelectorAll('.main-section li')
assert(els.length >= 5)
```

Você deve ter um elemento `nav` com o `id` `navbar`.

```js
const el = document.getElementById('navbar')
assert(!!el && el.tagName === 'NAV')
```

O elemento `#navbar` deve ter exatamente um elemento `header` dentro dele.

```js
const els = document.querySelectorAll('#navbar header')
assert(els.length === 1)
```

Você deve ter pelo menos um elemento `a` com a classe `nav-link`.

```js
const els = document.querySelectorAll('a.nav-link')
assert(els.length >= 1)
```

Todos os elementos com a classe `.nav-link` devem ser elementos âncora (`a`).

```js
const els = document.querySelectorAll('.nav-link')
els.forEach(el => {
  if (el.tagName !== 'A') assert(false)
})
assert(els.length > 0)
```

Todos os elementos com a classe `.nav-link` devem estar dentro de `#navbar`.

```js
const els1 = document.querySelectorAll('.nav-link')
const els2 = document.querySelectorAll('#navbar .nav-link')
assert(els2.length > 0 && els1.length === els2.length)
```

Você deve ter o mesmo número de elementos `.nav-link` e de elementos `.main-section`.

```js
const els1 = document.querySelectorAll('.main-section')
const els2 = document.querySelectorAll('.nav-link')
assert(els1.length > 0 && els2.length > 0 && els1.length === els2.length)
```

O elemento `header` em `#navbar` deve vir antes de qualquer elemento de link (`a`) que também esteja em `#navbar`.

```js
const navLinks = document.querySelectorAll('#navbar a.nav-link');
const header = document.querySelector('#navbar header');
navLinks.forEach((navLink) => {
  if (
    (
      header.compareDocumentPosition(navLink) &
      Node.DOCUMENT_POSITION_PRECEDING
    ) 
  ) assert(false)
});
assert(!!header)
```

Cada elemento com a classe `.nav-link` deve conter um texto que corresponda ao texto do `header` da `section` relacionada (por exemplo: se você tem uma seção/cabeçalho "Olá mundo", sua `#navbar` deve ter um elemento `.nav-link` que contenha o texto "Olá mundo").

```js
const headerText = Array.from(document.querySelectorAll('.main-section')).map(el =>
  el.firstElementChild?.innerText?.trim().toUpperCase()
)
const linkText = Array.from(document.querySelectorAll('.nav-link')).map(el =>
  el.innerText?.trim().toUpperCase()
)
const remainder = headerText.filter(str => linkText.indexOf(str) === -1)
assert(headerText.length > 0 && linkText.length > 0 && remainder.length === 0)
```

Cada `.nav-link` deve ter um atributo `href` que vincule à sua `.main-section` correspondente (por exemplo: se você clicar em um elemento `.nav-link` que contenha o texto "Olá mundo", a página navegará para o elemento `section` com aquele id).

```js
const hrefValues = Array.from(document.querySelectorAll('.nav-link')).map(el => el.getAttribute('href'))
const mainSectionIDs = Array.from(document.querySelectorAll('.main-section')).map(el => el.id)
const missingHrefValues = mainSectionIDs.filter(str => hrefValues.indexOf('#' + str) === -1)
assert(hrefValues.length > 0 && mainSectionIDs.length > 0 && missingHrefValues.length === 0)
```

O elemento `#navbar` deve estar sempre na parte superior da viewport.

```js
const el = document.getElementById('navbar')
const left1 = el?.offsetLeft
const left2 = el?.offsetLeft
assert(!!el && left1 >= -15 && left1 <= 15 && left2 >= -15 && left2 <= 15)
```

O projeto de documentação técnica deve utilizar pelo menos uma media query.

```js
const htmlSourceAttr = Array.from(document.querySelectorAll('source')).map(el => el.getAttribute('media'))
const cssCheck = new __helpers.CSSHelp(document).getCSSRules('media')
assert(cssCheck.length > 0 || htmlSourceAttr.length > 0);
```

# --seed--

## --seed-contents--

```html

```

```css

```

# --solutions--

```html
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <link rel="stylesheet" href="styles.css" />
    <title>Technical Documentation Page</title>
  </head>
  <body>
    <nav id="navbar">
      <header><br />Algebraic Concepts</header>
      <hr />
      <a href="#introduction" class="nav-link">Introduction</a><br />
      <hr />
      <a href="#definitions" class="nav-link">Definitions</a><br />
      <hr />
      <a href="#examples" class="nav-link">Examples</a><br />
      <hr />
      <a href="#solving_equations" class="nav-link">Solving Equations</a><br />
      <hr />
      <a href="#solving_equations_ii" class="nav-link">Solving Equations II</a
      ><br />
      <hr />
      <a href="#solving_equations_iii" class="nav-link">Solving Equations III</a
      ><br />
      <hr />
      <a href="#system_of_equations" class="nav-link">System of Equations</a
      ><br />
      <hr />
      <a href="#try_it_yourself!" class="nav-link">Try it Yourself!</a><br />
      <hr />
      <a href="#more_information" class="nav-link">More Information</a><br />
    </nav>
    <main id="main-doc">
      <section class="main-section" id="introduction">
        <header>Introduction</header>
        <p>
          Welcome to a basic introduction of algebra. In this tutorial, we will
          review some of the more common algebraic concepts.
        </p>
      </section>
      <section class="main-section" id="definitions">
        <header>Definitions</header>
        <p>
          To start with, let's define some of the more common terms used in
          algebra:
        </p>
        <ul>
          <li>
            <b>Variable:</b> A variable is an unknown value, usually represented
            by a letter.
          </li>
          <li>
            <b>Expression:</b> Essentially a mathematical object. For the
            purpose of this tutorial, an expression is one part of an equation.
          </li>
          <li>
            <b>Equation:</b> An equation is a mathematical argument in which two
            expressions result in the same value.
          </li>
        </ul>
      </section>
      <section class="main-section" id="examples">
        <header>Examples</header>
        <p>
          Sometimes it is easier to understand the definitions when you have a
          physical example to look at. Here is an example of the above terms.<br /><br />
          <code>x + 5 = 12 </code><br /><br />
          In this above example, we have:
        </p>
        <ul>
          <li><b>Variable:</b> The variable in the example is "x".</li>
          <li>
            <b>Expression:</b> There are two expressions in this example. They
            are "x+5" and "12".
          </li>
          <li>
            <b>Equation:</b> The entire example, "x+5=12", is an equation.
          </li>
        </ul>
      </section>
      <section class="main-section" id="solving_equations">
        <header>Solving Equations</header>
        <p>
          The primary use for algebra is to determine an unknown value, the
          "variable", with the information provided. Continuing to use our
          example from above, we can find the value of the variable "x".<br /><br />
          <code>x + 5 = 12 </code><br /><br />
          In an equation, both sides result in the same value. So you can
          manipulate the two expressions however you need, as long as you
          perform the same operation (or change) to each side. You do this
          because the goal when solving an equation is to
          <b
            >get the variable into its own expression, or by itself on one side
            of the = sign.</b
          ><br />For this example, we want to remove the "+5" so the "x" is
          alone. To do this, we can <em>subtract 5</em>, because subtraction is
          the opposite operation to addition. But remember, we have to perform
          the same operation to both sides of the equation. Now our equation
          looks like this.<br /><br />
          <code>x + 5 - 5 = 12 - 5</code><br /><br />
          The equation looks like a mess right now, because we haven't completed
          the operations. We can <b>simplify</b> this equation to make it easier
          to read by performing the operations "5-5" and "12-5". The result
          is:<br /><br />
          <code>x = 7</code><br /><br />
          We now have our solution to this equation!
        </p>
      </section>
      <section class="main-section" id="solving_equations_ii">
        <header>Solving Equations II</header>
        <p>
          Let us look at a slightly more challenging equation.<br /><br />
          <code>3x + 4 = 13</code><br /><br />
          Again we can start with subtraction. In this case, we want to subtract
          4 from each side of the equation. We will also go ahead and simplify
          with each step. So now we have:<br /><br />
          <code>3x = 9</code><br /><br />
          "3x" translates to "3*x", where the "*" symbol indicates
          multiplication. We use the "*" to avoid confusion, as the "x" is now a
          variable instead of a multiplication symbol. The opposite operation
          for multiplication is division, so we need to
          <b>divide each expression by 3</b>.<br /><br />
          <code>x = 3</code><br /><br />
          And now we have our solution!
        </p>
      </section>
      <section class="main-section" id="solving_equations_iii">
        <header>Solving Equations III</header>
        <p>
          Now we are getting in to more complex operations. Here is another
          equation for us to look at:<br /><br />
          <code>x^2 - 8 = 8</code><br /><br />
          Our very first step will be to <b>add</b> 8 to each side. This is
          different from our previous examples, where we had to subtract. But
          remember, our goal is to get the variable alone by performing opposite
          operations.<br /><br />
          <code>x^2 = 16</code><br /><br />
          But what does the "^2" mean? The "^" symbol is used to denote
          exponents in situations where superscript is not available. When
          superscript <b>is</b> available, you would see it as x<sup>2</sup>.
          For the sake of this project, however, we will use the "^" symbol.<br />
          An exponent tells you how many times the base (in our case, "x") is
          multiplied by itself. So, "x^2" would be the same as "x*x". Now the
          opposite function of multiplication is division, but we would have to
          <b>divide both sides by "x"</b>. We do not want to do this, as that
          would put an "x" on the other side of the equation. So instead, we
          need to use the root operation! For an exponent of "2", we call this
          the "square root" and denote it with "√". Our equation is now:
          <br /><br />
          <code>x = √9</code><br /><br />
          Performing a root operation by hand can be a tedious process, so we
          recommend using a calculator when necessary. However, we are lucky in
          that "9" is a
          <a href="https://en.wikipedia.org/wiki/Square_number"
            >perfect square</a
          >, so we do not need to calculate anything. Instead, we find our
          answer to be:<br /><br />
          <code>x = 3</code>
        </p>
      </section>
      <section class="main-section" id="system_of_equations">
        <header>System of Equations</header>
        <p>
          As you explore your algebra studies further, you may start to run
          across equations with more than one variable. The first such equations
          will likely look like:<br /><br />
          <code>y = 3x</code><br /><br />
          An equation like this does <b>not have one single solution</b>.
          Rather, there are a series of values for which the equation is true.
          For example, if "x=3" and "y=9", the equation is true. These equations
          are usually used to plot a graph. <br />
          Getting more complicated, though, you may be given a <b>pair</b> of
          equations. This is called a "system of equations", and CAN be solved.
          Let's look at how we do this! Consider the following system of
          equations:<br /><br />
          <code>y = 3x | y - 6 = x</code>
          A system of equations IS solvable, but it is a multi-step process. To
          get started, we need to choose a variable we are solving for. Let's
          solve for "x" first. From the second equation, we know that "x" equals
          "y - 6", but we cannot simplify that further because we do not have a
          value for "y". Except, thanks to the system of equations, we DO have a
          value for "y". We know that "y" equals "3x". So, looking at our second
          equation, we can replace "y" with "3x" because they have the same
          value. We then get:<br /><br />
          <code>3x - 6 = x</code><br /><br />
          Now we can solve for "x"! We start by adding 6 to each side.<br /><br />
          <code>3x = x + 6</code><br /><br />
          We still need to get "x" by itself, so we subtract "x" from both sides
          and get:<br /><br />
          <code>2x = 6</code><br /><br />
          If this confuses you, remember that "3x" is the same as "x+x+x".
          Subtract an "x" from that and you get "x+x", or "2x". Now we divide
          both sides by 2 and have our value for x!<br /><br />
          <code>x = 3</code><br /><br />
          However, our work is not done yet. We still need to find the value for
          "y". Let's go back to our first equation:<br /><br />
          <code>y = 3x</code><br /><br />
          We have a value for "x" now, so let's see what happens if we put that
          value in.<br /><br />
          <code>y = 3*3</code><br /><br />
          We perform the multiplication and discover that "y=9"! Our solution to
          this system of equations then is:<br /><br />
          <code>x = 3 and y = 9</code><br /><br />
        </p>
      </section>
      <section class="main-section" id="try_it_yourself!">
        <header>Try it Yourself!</header>
        <p>Coming Soon!</p>
        <p>Keep an eye out for new additions!</p>
      </section>
      <section class="main-section" id="more_information">
        <header>More Information</header>
        <p>Check out the following links for more information!</p>
        <ul>
          <li>
            <a href="https://www.wolframalpha.com/examples/mathematics/algebra/"
              >Wolfram Alpha</a
            >
            is a great source for multiple mathematic fields.
          </li>
          <li>
            <a href="https://en.wikipedia.org/wiki/Algebra"
              >Wikipedia's Algebra page</a
            >
            for more general information.
          </li>
        </ul>
      </section>
    </main>
  </body>
  <footer>
    <a href="../">Return to Project List</a> |
    <a href="https://www.nhcarrigan.com">Return to HomePage</a>
  </footer>
</html>
```

```css
* {
  background-color: #3a3240;
}
a {
  color: #92869c;
}
a:hover {
  background-color: #92869c;
  color: #3a3240;
}
#navbar {
  border-style: solid;
  border-width: 5px;
  border-color: #92869c;
  height: 100%;
  top: -5px;
  left: -5px;
  padding: 5px;
  text-align: center;
  color: #92869c
}
@media (min-width: 480px) {
  #navbar {
    position: fixed;
  }
}
main {
  margin-left: 220px;
  color: #92869c
}
header {
  font-size: 20pt;
}
code {
  background-color: #92869c;
  border-style: dashed;
  border-width: 2px;
  border-color: #92869c;
  padding: 5px;
  color: black;
}
footer {
  text-align: center;
}
```
